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2019-10-05
Adsorption, desorption, and interdiffusion in atomic layer epitaxy of CdTe and CdZnTe
The mechanisms controlling the growth rate and composition of epitaxial CdTe and CdZnTe films were studied. The films were grown by isothermal closed space configuration technique. A GaAs 100 substrate was exposed sequentially to the elemental sources, Zn, Te, and Cd, in isothermal conditions. While growth of ZnTe foll...
1910.02944v1
2019-10-13
Phonon-assisted diffusion in bcc phase of titanium and zirconium from first-principles
Diffusion is the underlying mechanism for many complicated materials phenomena, and understanding it is basic to the discovery of novel materials with desired physical and mechanical properties. Certain groups of solid phases, such as the bcc phase of IIIB and IVB metals and their alloys, which are only stable when the...
1910.05806v2
2019-10-18
Design and operation of the air-cooled beam dump for the extraction line of CERN's Proton Synchrotron Booster (PSB)
A new beam dump has been designed, built, installed and operated to withstand the future proton beam extracted from the Proton Synchrotron Booster (PSB) in the framework of the LHC Injector Upgrade (LIU) Project at CERN, consisting of up to 1E14 protons per pulse at 2 GeV, foreseen after the machine upgrades planned fo...
1910.08493v4
2019-10-25
Theory of transformation-mediated twinning
High-density and nanosized deformation twins in face-centered cubic (fcc)materials can effectively improve the combination of strength and ductility. However, the microscopic dislocation mechanisms enabling a high twinnability remain elusive. Twinning usually occurs via continuous nucleation and gliding of twinning par...
1910.11748v2
2012-09-11
Analysis of acoustic emission during the melting of embedded indium particles in an aluminum matrix: a study of plastic strain accommodation during phase transformation
Acoustic emission is used here to study melting and solidification of embedded indium particles in the size range of 0.2 to 3 um in diameter and to show that dislocation generation occurs in the aluminum matrix to accommodate a 2.5% volume change. The volume averaged acoustic energy produced by indium particle melting ...
1209.2454v1
2014-06-01
Diffusivities and kinetics of short-range and long-range orderings in Ni-Fe permalloys
The microscopic model of atomic diffusion is considered to describe the short-range order relaxation kinetics within the f.c.c.-Ni-Fe Permalloys. The model takes into account both the discrete and anisotropic characters of atomic jumps within the long-range field of concentration heterogeneities of the interacting atom...
1406.0147v1
2014-06-17
First-principles study of the electronic structure of CdS/ZnSe coupled quantum dots
We have studied the electronic structure of CdS/ZnSe coupled quantum dot, a novel heterostructure at the nano-scale. Our calculations reveal CdS/ZnSe coupled quantum dots to be of type-II in nature where the anion-p states play an important role in deciding the band offset for the highest occupied molecular orbitals (H...
1406.4487v1
2014-06-20
Cluster Altered Magnetic and Transport Properties in Eu Co-Doped Ge(1-x)Mn(x)Te
Magnetic and transport properties of Ge(1-x-y)Mn(x)Eu(y)Te crystals with chemical compositions 0.041 < x < 0.092 and 0.010 < y < 0.043 are studied. Ferromagnetic order is observed at 150 < T < 160 K. Aggregation of magnetic ions into clusters is found to be the source of almost constant, composition independent Curie t...
1406.5289v1
2014-06-20
From itinerant to local transformation and critical point in Ni-rich Ce_2(Ni_{1-y}Pd_y)_2Sn
Structural, magnetic (M) and thermal (C_m) studies on Ce_2(Ni_{1-y}Pd_y)_2Sn alloys are presented within the 0<y<0.55 range of concentration, showing evidences for itinerant to local electronic transformation. At variance with RKKY type interactions between localized moments \mu_{eff}, the substitution of Ni by isoelec...
1406.5380v1
2018-02-07
Towards a Simple, and Yet Accurate, Transistor Equivalent Circuit and Its Application to the Analysis and Design of Discrete and Integrated Electronic Circuits
Transistors are the cornerstone of modern electronics. Yet, their relatively complex characteristics, allied with often observed great parameter variation, remain a challenge for discrete and integrated electronics. Much of transistor research and applications have relied on transistor models, as well as respective equ...
1802.02279v1
2018-02-08
Self-ordered nanostructures on patterned substrates: Experiment and theory of metalorganic vapor-phase epitaxy of V-groove quantum wires and pyramidal quantum dots
The formation of nanostructures during metalorganic vapor-phase epitaxy on patterned (001)/(111)B GaAs substrates is reviewed. The focus of this review is on the seminal experiments that revealed the key kinetic processes during nanostructure formation and the theory and modelling that explained the phenomenology in su...
1802.02823v1
2018-02-13
High Mobility 2DEG in modulation-doped \b{eta}-(AlxGa1-x)2O3/Ga2O3 heterostructures
Beta-phase Ga2O3 has emerged as a promising candidate for a wide range of device applications, including power electronic devices, radio-frequency devices and solar-blind photodetectors. The wide bandgap energy and the predicted high breakdown field, together with the availability of low-cost native substrates, make \b...
1802.04426v1
2018-02-23
Crystal structure and local ordering in epitaxial Fe$_{100-x}$Ga$_x$/MgO(001) films
In this work we present a study of the structural properties of Fe$_{100-x}$ Ga$_x$ grown by Molecular Beam Epitaxy on Mg0(100). We combine long range and local/chemically selective X-ray probes (X-ray Diffraction and X-ray absorption spectroscopy) together with real space imaging by means of Transmission Electron Micr...
1802.08740v2
2018-02-26
Magnetic order and disorder in nanomagnets probed by superconducting vortices
We have studied two nanomagnet systems with strong (Co/Pd multilayers) and weak (NdCo alloy films) stray magnetic fields by probing the out-of-plane magnetic states with superconducting vortices. The hybrid samples are made of array of nanomagnets embedded in superconducting Nb thin films. The vortex motion detects rel...
1802.09633v3
2018-08-03
Giant magnetocaloric effect driven by indirect exchange in magnetic multilayers
Indirect exchange coupling in magnetic multilayers, also known as the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, is known to be highly effective in controlling the interlayer alignment of the magnetization. This coupling is typically fixed at the stage of the multilayer fabrication and does not allow ex-situ con...
1808.01291v3
2018-08-13
Improvement of superconducting properties by high mixing entropy at blocking layers in BiS2-based superconductor REO0.5F0.5BiS2
To investigate the interlayer interaction in the recently synthesized high-entropy-alloy-type (HEA-type) REO0.5F0.5BiS2 superconductors (RE: rare earth), we have systematically synthesized samples with close lattice parameters and different mixing entropy (DSmix) for the RE site. The crystal structure was investigated ...
1808.04090v2
2018-08-21
Smart energy models for atomistic simulations using a DFT-driven multifidelity approach
The reliability of atomistic simulations depends on the quality of the underlying energy models providing the source of physical information, for instance for the calculation of migration barriers in atomistic Kinetic Monte Carlo simulations. Accurate (high-fidelity) methods are often available, but since they are usua...
1808.06935v2
2018-12-05
Substrate-dependent Photoconductivity Dynamics in a High-efficiency Hybrid Perovskite Alloy
Films of (FA$_{0.79}$MA$_{0.16}$Cs$_{0.05}$)$_{0.97}$Pb(I$_{0.84}$Br$_{0.16}$)$_{2.97}$ were grown over TiO$_{2}$, SnO$_{2}$, ITO, and NiO. Film conductivity was interrogated by measuring the in-phase and out-of-phase forces acting between the film and a charged microcantilever. We followed the films' conductivity vs. ...
1812.02135v2
2018-12-17
Tuning bimetallic catalysts for a selective growth of SWCNTs
Recent advances in structural control during the synthesis of SWCNTs have in common the use of bimetallic nanoparticles as catalysts, despite the fact that their exact role is not fully understood. We therefore analyze the effect of the catalyst' s chemical composition on the structure of the resulting SWCNTs by compar...
1812.06118v1
2018-12-13
Analytical, numerical and experimental investigation of Luneburg lens system for directional cloaking
In this study, the design of a directional cloaking based on the Luneburg lens system is proposed and its operating principle is experimentally verified. The cloaking concept is analytically investigated via geometrical optics and numerically realized with the help of the finite-difference time-domain method. In order ...
1812.06179v2
2018-12-19
A non-linear minimization calculation of the renormalized frequency $\tildeω$ in dirty d-wave superconductors
This work performs a comparative numerical study of the impurity average self-frequency $\tilde{\omega}$ in an unconventional superconducting alloy with non-magnetic impurities. Two methods are used: the Levenberg-Marquardt algorithm as a non-linear minimization problem, and a fixed-point iteration procedure. The uncon...
1812.08165v2
2019-02-10
Unconventional anomalous Hall effect in 3d/5d multilayers mediated by the nonlocal spin-conductivity
We evidenced unconventionnal Anomalous Hall Effects (AHE) in 3d/5d (Co0.2nm/Ni0.6nm)N multilayers grown on a thin Pt layer or thin Au:W alloy. The inversion observed on AHE originates from the opposite sign of the spin-orbit coupling of Pt compared to Ni. Via advanced simulations methods for the description of the spin...
1902.03564v2
2019-02-11
Stable, carbon-free inks of Cu2ZnSnS4 nanoparticles synthesized at room temperature designed for roll-to-roll fabrication of solar cell absorber layers
We report on a novel room temperature approach for the synthesis of environmentally-friendly copper zinc tin sulfide ($Cu_2ZnSnS_4$) nanoparticles. The method is shown to be compositionally robust and able to produce $S^{2-}$-stabilized carbon-free nanoparticle inks that are suitable for an absorber layer in solar cell...
1902.04044v2
2019-02-20
Epitaxial strain adaption in chemically disordered FeRh thin films
Strain and strain adaption mechanisms in modern functional materials are of crucial importance for their performance. Understanding these mechanisms will advance innovative approaches for material properties engineering. Here we study the strain adaption mechanism in a thin film model system as function of epitaxial st...
1902.07596v2
2019-06-05
Pattern Formation Mechanism of Directionally-Solidified MoSi2/Mo5Si3 Eutectic by Phase-Field Simulation
A phase-field study has been conducted to obtain an understanding of the formation mechanism of the script lamellar pattern of MoSi2/Mo5Si3 eutectic composite, which is a promising candidate for high-temperature structural application. The spacing of the lamellar pattern in the simulation results shows good agreement w...
1906.01814v2
2019-06-05
Thermal chiral anomaly in the magnetic-field induced ideal Weyl phase of Bi1-xSbx topological insulators
The chiral anomaly is the predicted break down of chiral symmetry in a Weyl semimetal with monopoles of opposite chirality when an electric field parallel to a magnetic field is applied. It occurs because of charge pumping from a positive chirality to a negative chirality monopole. Experimental observation of this fund...
1906.02248v3
2019-06-10
Site-resolved hyperfine and lattice dynamical properties of a single-crystal Fe3Si
A single-crystal sample of a DO3-ordered Fe3Si compound was studied by means of the 57Fe M\"ossbauer spectroscopy. Spectra have been recorded in a transmission geometry in the temperature range between 5 and 850 K. They have been analyzed either in terms of five sextets or five hyperfine field distribution curves. Conc...
1906.03946v1
2019-05-31
High-low level support vector regression prediction approach (HL-SVR) for data modeling with input parameters of unequal sample sizes
Support vector regression (SVR) has been widely used to reduce the high computational cost of computer simulation. SVR assumes the input parameters have equal sample sizes, but unequal sample sizes are often encountered in engineering practices. To solve this issue, a new prediction approach based on SVR, namely as hig...
1906.05777v1
2019-06-18
Effect of grain-boundary diffusion process on the geometry of the grain microstructure of Nd$-$Fe$-$B nanocrystalline magnets
Hot-deformed anisotropic Nd$-$Fe$-$B nanocrystalline magnets have been subjected to the grain-boundary diffusion process (GBDP) using a $\mathrm{Pr}_{70}\mathrm{Cu}_{30}$ eutectic alloy. The resulting grain microstructure, consisting of shape-anisotropic Nd$-$Fe$-$B nanocrystals surrounded by a Pr$-$Cu-rich intergranul...
1906.07388v1
2019-06-20
Predicting the Curie temperature of ferromagnets using machine learning
The magnetic properties of a material are determined by a subtle balance between the various interactions at play, a fact that makes the design of new magnets a daunting task. High-throughput electronic structure theory may help to explore the vast chemical space available and offers a design tool to the experimental s...
1906.08534v1
2019-06-24
Weak ferromagnetism in hexagonal Mn3Z (Z=Sn, Ge, Ga) alloys
We present combined spin model and first principles electronic structure calculations to study the weak ferromagnetism in bulk Mn$_3$Z (Z=Sn, Ge, Ga) compounds. The spin model parameters were determined from a spin-cluster expansion technique based on the relativistic disordered local moment formalism implemented in th...
1906.10062v1
2019-06-26
Suppressed Auger scattering and tunable light emission of Landau-quantized massless Kane electrons
The Landau level laser has been proposed a long time ago as a unique source of monochromatic radiation, widely tunable in the THz and infrared spectral ranges using an externally applied magnetic field. In spite of decades of efforts, this appealing concept never resulted in the design of a reliable device. This is due...
1906.10905v2
2019-06-27
Kinetic Control of Morphology and Composition in Ge/GeSn Core/Shell Nanowires
The growth of Sn-rich group-IV semiconductors at the nanoscale provides new paths for understanding the fundamental properties of metastable GeSn alloys. Here, we demonstrate the effect of the growth conditions on the morphology and composition of Ge/GeSn core/shell nanowires by correlating the experimental observation...
1906.11694v3
2020-04-02
Spinodal decomposition versus classical gamma-prime nucleation in a nickel-base superalloy powder: An in-situ neutron diffraction and atomic-scale analysis
Contemporary powder-based polycrystalline nickel-base superalloys inherit microstructures and properties that are heavily determined by the thermo-mechanical treatments during processing. Here, the influence of a thermal exposure alone to an alloy powder is studied to elucidate the controlling formation mechanisms of t...
2004.01146v2
2020-04-09
Exploration of lattice Hamiltonians for functional and structural discovery via Gaussian Process-based Exploration-Exploitation
Statistical physics models ranging from simple lattice to complex quantum Hamiltonians are one of the mainstays of modern physics, that have allowed both decades of scientific discovery and provided a universal framework to understand a broad range of phenomena from alloying to frustrated and phase-separated materials ...
2004.04832v4
2020-04-12
Fabrication process and failure analysis for robust quantum dots in silicon
We present an improved fabrication process for overlapping aluminum gate quantum dot devices on Si/SiGe heterostructures that incorporates low-temperature inter-gate oxidation, thermal annealing of gate oxide, on-chip electrostatic discharge (ESD) protection, and an optimized interconnect process for thermal budget con...
2004.05683v3
2020-05-01
Tunable Ferromagnetism and Thermally Induced Spin Flip in Vanadium-doped Tungsten Diselenide Monolayers at Room Temperature
The outstanding optoelectronic and valleytronic properties of transition metal dichalcogenides (TMDs) have triggered intense research efforts by the scientific community. An alternative to induce long-range ferromagnetism (FM) in TMDs is by introducing magnetic dopants to form a dilute magnetic semiconductor. Enhancing...
2005.00493v1
2020-05-07
Prediction of the Al-rich part of the Al-Cu phase diagram using cluster expansion and statistical mechanics
The thermodynamic properties of {\alpha}-Al and other phases (GP zones, {\theta}'', {\theta}' and {\theta}) in the Al-rich part of the Al-Cu system have been obtained by means of the cluster expansion formalism in combination with statistical mechanics. This information was used to build the Al-rich part of the Al-Cu p...
2005.03605v1
2020-05-08
Sublattice magnetizations of ultrathin ferrimagnetic lamellar nanostructures between cobalt leads
In this work we model the salient magnetic properties of the alloy lamellar ferrimagnetic nanostructures $[Co_{1-c}Gd_c]_{\ell^{\prime}}[Co]_\ell[Co_{1-c}Gd_c]_{\ell^{\prime}}$ between $Co$ semi-infinite leads. We have employed the Ising spin effective field theory (EFT) to compute the reliable magnetic exchange consta...
2005.03965v3
2020-04-18
Information Content of Hierarchical n-Point Polytope Functions for Quantifying and Reconstructing Disordered Systems
Disordered systems are ubiquitous in physical, biological and material sciences. Examples include liquid and glassy states of condensed matter, colloids, granular materials, porous media, composites, alloys, packings of cells in avian retina and tumor spheroids, to name but a few. A comprehensive understanding of such ...
2005.06391v1
2020-05-14
T2 phase site occupancies in the Cr--Si--B system: a combined synchroton-XRD/first-principles study
Boron and Silicon site occupancies of the T2 phase in the Cr-Si-B system were investigated experimentally and by first-principles electronic-structure calculations within the scope of the Density Functional Theory (DFT). A sample with nominal composition Cr$_{0.625}$B$_{0.175}$Si$_{0.2}$ was arc-melted under argon, enc...
2005.06900v4
2020-08-05
Atomistic simulation of martensite microstructural evolution during temperature driven $β\rightarrow α$ transition in pure titanium
Titanium and its alloys undergo temperature-driven martensitic phase transformation leading to the development of complex microstructures at mesoscale. Optimizing the mechanical properties of these materials requires an understanding of the correlations between the processing parameters and the mechanisms involved in t...
2008.02128v2
2020-08-11
Grain refinement of stainless steel in ultrasound-assisted additive manufacturing
Metals and alloys fabricated by fusion-based additive manufacturing (AM), or 3D printing, undergo complex dynamics of melting and solidification, presenting challenges to the effective control of grain structure. Herein, we report on the use of high-intensity ultrasound that controls the process of solidification durin...
2008.04485v3
2020-08-11
Investigating the ranges of (meta)stable phase formation in (InxGa1-x)2O3: Impact of the cation coordination
We investigate the phase diagram of the heterostructural solid solution (InxGa1-x)2O3 both computationally, by combining cluster expansion and density functional theory, and experimentally, by means of TEM measurements of pulsed laser deposited (PLD) heteroepitaxial thin films. The shapes of the Gibbs free energy curve...
2008.04573v1
2020-08-12
Symmetry driven topological phases in XAgBi (X=Ba,Sr): An Ab-initio hybrid functional calculations
Density functional theory (DFT) approaches have been ubiquitously used to predict topological order and non-trivial band crossings in real materials, like Dirac, Weyl semimetals and so on. However, use of less accurate exchange-correlation functional often yields false prediction of non-trivial band order leading to mi...
2008.05108v1
2020-08-15
Electrically Reconfigurable Nonvolatile Metasurface Using Low-Loss Optical Phase Change Material
Active metasurfaces promise reconfigurable optics with drastically improved compactness, ruggedness, manufacturability, and functionality compared to their traditional bulk counterparts. Optical phase change materials (O-PCMs) offer an appealing material solution for active metasurface devices with their large index co...
2008.06659v2
2020-08-17
Phonon-based partition of (ZnSe-like) semiconductor mixed crystals on approach to their pressure-induced structural transition
The generic 1-bond:2-mode percolation type Raman signal inherent to the short bond of common (A,B)C semiconductor mixed crystals with zincblende (cubic) structure is exploited as a sensitive mesoscope to explore how various ZnSe-based systems engage their pressure-induced structural transition (to rock-salt) at the sub...
2008.07187v1
2020-08-20
Antimony thin films demonstrate programmable optical non-linearity
The use of metals of nanometer dimensions to enhance and manipulate light-matter interactions for a range of emerging plasmonics-enabled nanophotonic and optoelectronic applications is an interesting, yet not highly explored area of research outside of plasmonics1,2. Even more importantly, the concept of an active meta...
2008.09007v1
2020-08-25
Variable selection for Gaussian process regression through a sparse projection
This paper presents a new variable selection approach integrated with Gaussian process (GP) regression. We consider a sparse projection of input variables and a general stationary covariance model that depends on the Euclidean distance between the projected features. The sparse projection matrix is considered as an unk...
2008.10769v1
2020-08-27
Probing efficient n-type lanthanide dopants for Mg$_3$Sb$_2$ thermoelectrics
The recent discovery of n-type Mg$_3$Sb$_2$ thermoelectric has ignited intensive research activities on searching for potential n-type dopants for this material. Using first-principles defect calculations, here we conduct a systematic computational screening of potential efficient n-type lanthanide dopants for Mg$_3$Sb...
2008.12015v1
2020-08-28
Uncovering the role of the density of states in controlling ultrafast spin dynamics
At the ultrafast limit of optical spin manipulation is the theoretically predicted phenomena of optical intersite spin transfer (OISTR), in which laser induced charge transfer between the sites of a multi-component material leads to control over magnetic order. A key prediction of this theory is that the demagnetizatio...
2008.12612v2
2021-03-01
Sub-second and ppm-level Optical Sensing of Hydrogen Using Templated Control of Nano-hydride Geometry and Composition
The use of hydrogen as a clean and renewable alternative to fossil fuels requires a suite of flammability mitigating technologies, particularly robust sensors for hydrogen leak detection and concentration monitoring. To this end, we have developed a class of lightweight optical hydrogen sensors based on a metasurface o...
2103.01011v1
2021-03-09
Unconventional short-range structural fluctuations in cuprate high-$T_c$ superconductors
The interplay between structural and electronic degrees of freedom in complex materials is the subject of extensive debate in physics and materials science. Particularly interesting questions pertain to the nature and extent of pre-transitional short-range order in diverse systems ranging from shape-memory alloys to un...
2103.05482v3
2021-03-10
Eigenmodes of a disordered FeCo magnonic crystal at finite temperatures
In this report we present a systematic study of the magnonic modes in the disordered Fe$_{0.5}$Co$_{0.5}$ alloy based on the Heisenberg Hamiltonian using two complementary approaches. In order to account for substitutional disorder, on the one hand we directly average the transverse magnetic susceptibility in real spac...
2103.05967v2
2021-03-26
A tale of two phase diagrams: Interplay of ordering and hydrogen uptake in Pd-Au-H
Due to their ability to reversibly absorb/desorb hydrogen without hysteresis, Pd--Au nanoalloys have been proposed as materials for hydrogen sensing. For sensing, it is important that absorption/desorption isotherms are reproducible and stable over time. A few studies have pointed to the influence of short and long ran...
2103.14340v1
2021-03-29
Synthesis of Three-Dimensionally Interconnected Hexagonal Boron Nitride Networked Cu-Ni Composite
A three-dimensionally interconnected hexagonal boron nitride (3Di-hBN) networked Cu-Ni (3Di-hBN-Cu-Ni) composite was successfully synthesized in situ using a simple two-step process which involved the compaction of mixed Cu-Ni powders (70 wt.% Cu and 30 wt.% Ni) into a disc followed by metal-organic chemical vapor depo...
2103.15392v1
2021-03-29
The improved inverted AlGaAs/GaAs interface: its relevance for high-mobility quantum wells and hybrid systems
Two dimensional electron gases (2DEGs) realized at GaAs/AlGaAs single interfaces by molecular-beam epitaxy (MBE) reach mobilities of about 15 million cm^2/Vs if the AlGaAs alloy is grown after the GaAs. Surprisingly, the mobilities may drop to a few millions for the identical but inverted AlGaAs/GaAs interface, i.e. re...
2103.15935v3
2022-01-30
Ultrahigh-Pressure Magnesium Hydrosilicates as Reservoirs of Water in Early Earth
The origin of water on the Earth is a long-standing mystery, requiring a comprehensive search for hydrous compounds, stable at conditions of the deep Earth and made of Earth-abundant elements. Previous studies usually focused on the current range of pressure-temperature conditions in the Earth's mantle and ignored a po...
2202.00752v1
2022-02-04
Theory of Disordered Superconductors with Applications to Nonlinear Current Response
I present a review of the theory and basic equations for charge transport in superconducting alloys starting from the Keldysh formulation of the quasiclassical transport equations developed by Eilenberger, Larkin and Ovchinnikov and Eliashberg. This formulation is the natural extension of Landau's theory of normal Ferm...
2202.02260v2
2022-02-07
Coulomb correlations and magnetic properties of L1$_0$ FeCo: a DFT+DMFT study
We consider electronic correlation effects and their impact on magnetic properties of tetragonally distorted chemically ordered FeCo alloys (L1$_0$ structure) being a promising candidate for rare-earth-free permanent magnets. We employ a state-of-the-art method combining density functional and dynamical mean-field theo...
2202.03205v2
2022-02-09
Hole conductivity through a defect band in $\rm ZnGa_2O_4$
Semiconductors with wide band gap (3.0 eV), high dielectric constant (> 10), good thermal dissipation, and capable of $n$- and $p$-type doping are highly desirable for high-energy power electronic devices. Recent studies indicate that $\rm ZnGa_2O_4$ may be suitable for these applications, standing out as an alternativ...
2202.04698v1
2022-02-11
Room Temperature Magnetocaloric Effect In CrTe1-XSex Alloys
Polycrystalline CrTe1-xSex samples were prepared using the conventional solid-state reaction technique and characterized by x-rad diffraction, temperature- and field- dependent magnetization for possible use in magnetocaloric cooling. Rietveld refinement revealed two phases in all prepared samples; a minor monoclinic p...
2202.05624v2
2022-02-18
The effect of hydrogen on the multiscale mechanical behaviour of a La(Fe,Mn,Si)13-based magnetocaloric material
Magnetocaloric cooling offers the potential to improve the efficiency of refrigeration devices and hence cut the significant CO2 emissions associated with cooling processes. A critical issue in deployment of this technology is the mechanical degradation of the magnetocaloric material during processing and operation, le...
2202.09148v1
2022-02-18
Synergism between B and Nb improves fire resistance in microalloyed steels
The development of new fire-resistant steels represents a challenge in materials science and engineering of utmost importance. Alloying elements such as Nb and Mo are generally used to improve the strength at both room- and high-temperatures due to, for example, the formation of precipitates and harder microconstituent...
2202.09197v1
2022-02-28
Thermodynamic modeling of the Pd-Zn system with uncertainty quantification and its implication to tailor catalysts
Pd-Zn intermetallic catalysts show encouraging combinations of activity and selectivity on well-defined active site ensembles. Thermodynamic description of the Pd-Zn system, delineating phase boundaries, and enumerating site occupancies within intermediate alloy phases, are essential to determining the ensembles of Pd-...
2203.00044v2
2022-03-09
All-optical switching on the nanometer scale excited and probed with femtosecond extreme ultraviolet pulses
Ultrafast control of magnetization on the nanometer length scale, in particular all-optical switching, is key to putting ultrafast magnetism on the path towards future technological application in data storage technology. However, magnetization manipulation with light on this length scale is challenging due to the wave...
2203.04996v2
2022-03-10
Superconducting dome by tuning through a Van Hove singularity in a two-dimensional metal
Chemical substitution is a promising route for the exploration of a rich variety of doping- and/or disorder-dependent collective phenomena in low-dimensional quantum materials. Here we show that transition metal dichalcogenide alloys are ideal platforms to this purpose. In particular, we demonstrate the emergence of su...
2203.05650v3
2022-03-15
Confining Eutectic Gallium Indium (eGaIn) in Expired Artificial Kidneys to Unveil Nanoporous Conductive Wires
Nanoporous membranes have gained considerable interest in drug delivery1, ion transportation2, micro/nanofluidics3, molecular sensing4, and separation science5. Artificial kidneys, also known as dialyzers, reject pathogens and other unwanted substances from the blood, utilize hundreds of soft and nanoporous polymeric m...
2203.07744v1
2022-03-27
Enhancement of the superconducting critical temperature realized in the La-Ce-H system at moderate pressures
Covalent and ionic polyhydrides have become the two main camps in searching for the high-temperature superconductors under pressure. They have been considered as important platforms for exploring ternary or multiple hydrides in order to further increase the Tc or decrease the stabilization pressure. In this work, we su...
2203.14353v2
2022-03-30
Tin (Sn) at high pressure: review, X-ray diffraction, DFT calculations, and Gibbs energy modeling
An assessment of the Sn unary system is presented. First, the literature on phase equilibria, the thermodynamic properties, the volume and related properties, and shock compression of tin is thoroughly reviewed. Second, the Sn system is investigated by means of synchrotron X-ray diffraction in a diamond-anvil cell up t...
2203.16240v2
2016-03-06
Strain-induced structural instability in FeRh
We perform density functional calculations to investigate the structure of the inter-metallic alloy FeRh under epitaxial strain. Bulk FeRh exhibits a metamagnetic transition from a low-temperature antiferromagnetic (AFM) phase to a ferromagnetic (FM) phase at 350K, and its strain dependence is of interest for tuning th...
1603.01827v1
2016-03-11
Colloquium: Topological Band Theory
The first-principles band theory paradigm has been a key player not only in the process of discovering new classes of topologically interesting materials, but also for identifying salient characteristics of topological states, enabling direct and sharpened confrontation between theory and experiment. We begin this revi...
1603.03576v1
2016-03-14
Double-phase transition and giant positive magnetoresistance in the quasi-skutterudite Gd$_3$Ir$_4$Sn$_{13}$
The magnetic, thermodynamic and electrical/thermal transport properties of the caged-structure quasi-skutterudite Gd$_3$Ir$_4$Sn$_{13}$ are re-investigated. The magnetization $M(T)$, specific heat $C_p(T)$ and the resistivity $\rho(T)$ reveal a double-phase transition -- at $T_{N1}\sim$ 10~K and at $T_{N2}\sim$ 8.8~K -...
1603.04377v1
2016-03-23
Marangoni driven turbulence in high energy surface melting processes
Experimental observations of high-energy surface melting processes, such as laser welding, have revealed unsteady, often violent, motion of the free surface of the melt pool. Surprisingly, no similar observations have been reported in numerical simulation studies of such flows. Moreover, the published simulation result...
1603.07124v1
2016-12-08
Elucidating the Voltage Controlled Magnetic Anisotropy
Voltage controlled magnetic anisotropy (VCMA) is an efficient way to manipulate the magnetization states in nanomagnets, promising for low-power spintronic applications. The underlying physical mechanism for VCMA is known to involve a change in the d-orbital occupation on the transition metal interface atoms with an ap...
1612.02724v1
2016-12-12
Synthesis and properties of A$_x$V$_2$Al$_{20}$ (A = Th, U, Np, Pu) ternary actinide aluminides
Polycrystalline samples of A$_x$V$_2$Al$_{20}$ (A = Ce, Th, U, Np, Pu; 0.7 =< x =< 1.0) actinide intermetallics were synthesized using the arc-melting method. Crystal structure studies were performed by means of powder x-ray diffraction and the Rietveld refinement method. All studied compounds crystallize in the CeCr$_...
1612.03609v1
2016-12-20
Magnetism of PrFeAsO parent compound for iron-based superconductors: Mössbauer spectroscopy study
Moessbauer spectroscopy measurements were performed for the temperature range between 4.2 K and 300 K in a transmission geometry applying 14.41-keV resonant line in 57Fe for PrFeAsO the latter being a parent compound of the iron-based superconductors belonging to the '1111' family. It was found that an itinerant 3d mag...
1612.06776v3
2016-12-20
Magnetocrystalline anisotropy of Laves phase Fe$_2$Ta$_{1-x}$W$_x$ from first principles - the effect of 3d-5d hybridisation
The magnetic properties of Fe$_2$Ta and Fe$_2$W in the hexagonal Laves phase are computed using density functional theory in the generalised gradient approximation, with the full potential linearised augmented plane wave method. The alloy Fe$_2$Ta$_{1-x}$W$_x$ is studied using the virtual crystal approximation to treat...
1612.06802v1
2016-12-22
Band-gap tuning and optical response of two-dimensional Si$_x$C$_{1-x}$: A first-principles real space study of disordered 2D materials
We present a real-space formulation for calculating the electronic structure and optical conductivity of such random alloys based on the Kubo-Greenwood formalism interfaced with the augmented space recursion (ASR) [A. Mookerjee, J. Phys. C: Solid State Phys. {\bf 6}, 1340 (1973)] formulated with the Tight-binding Linea...
1612.07713v5
2017-02-08
A continuum approach to combined $γ/γ'$ evolution and dislocation plasticity in Nickel-based superalloys
Creep in single crystal Nickel-based superalloys has been a topic of interest since decades, and nowadays simulations are more and more able to complement experiments. In these alloys, the $\gamma/\gamma'$ phase microstructure co-evolves with the system of dislocations under load, and understanding the mutual interacti...
1702.02386v1
2017-02-10
Mechanical behavior, bonding nature, and defect processes of Mo2ScAlC2: a new ordered MAX phase
In the present study we employed density functional theory calculations to investigate the mechanical behavior, bonding nature and defect processes of the new ordered MAX phase Mo2ScAlC2. The mechanical stability of the compound is verified with its single crystal elastic constants. The new phase Mo2ScAlC2 is anticipat...
1702.03048v1
2017-02-22
Superconductivity and quantum criticality in heavy fermions CeIrSi$_3$ and CeRhSi$_3$
Superconductivity and magnetism are mutually exclusive in most alloys and elements, so it is striking that superconductivity emerges around a magnetic quantum critical point (QCP) in many strongly correlated electron systems (SCES). In the latter case superconductivity is believed to be unconventional and directly infl...
1702.06812v2
2017-06-02
Relationship between critical current and flux-flow resistivity in the mixed state of Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$
We studied the temperature and magnetic field dependence of vortex dissipation and critical current in the mixed-state of unconventional superconducting alloys Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ ($0.044 \leq x \leq 0.100$) through current-voltage measurements. Our results reveal that all the electric field $E$ vs current d...
1706.00543v1
2017-06-05
Erasing and Correction of Liquid Metal Printed Electronics Made of Gallium Alloy Ink from the Substrate
Gallium-based liquid metals have recently been found important in a variety of newly emerging applications such as room temperature metal 3D printing, direct writing of electronics and biomedicine etc. In all these practices, one frequently encounters the situations that a printed circuit or track needs to be corrected...
1706.01457v1
2017-06-07
\textit{Ab Initio} Study of the Magnetic Behavior of Metal Hydrides: A Comparison with the Slater-Pauling Curve
We investigated the magnetic behavior of metal hydrides FeH$_{x}$, CoH$_{x}$ and NiH$_{x}$ for several concentrations of hydrogen ($x$) by using Density Functional Theory calculations. Several structural phases of the metallic host: bcc ($\alpha$), fcc ($\gamma$), hcp ($\varepsilon$), dhcp ($\varepsilon'$), tetragonal ...
1706.02285v2
2017-06-11
Structural, elastic, electronic, and bonding properties of intermetallic Nb3Pt and Nb3Os compounds: a DFT study
Theoretical investigation of structural, elastic, electronic and bonding properties of A-15 Nb-based intermetallic compounds Nb3B (B = Pt, Os) have been performed using first principles calculations based on the density functional theory (DFT). Optimized cell parameters are found to be in good agreement with available ...
1706.03314v1
2017-06-13
Novel Exotic Magnetic Spin-order in Co5Ge3 Nano-size Materials
The Cobalt-germanium (Co-Ge) is a fascinating complex alloy system that has unique structure and exhibit range of interesting magnetic properties which would change when reduce to nanoscale dimension. At this experimental work, the high-aspect-ratio Co5Ge3 nanoparticle with average size of 8nm was synthesized by gas ag...
1706.04271v2
2017-06-19
Investigation of the Dzyaloshinskii-Moriya interaction and room temperature skyrmions in W/CoFeB/MgO thin films and microwires
Recent studies have shown that material structures, which lack structural inversion symmetry and have high spin-orbit coupling can exhibit chiral magnetic textures and skyrmions which could be a key component for next generation storage devices. The Dzyaloshinskii-Moriya Interaction (DMI) that stabilizes skyrmions is a...
1706.05987v1
2017-06-23
Upgrade of the ultracold neutron source at the pulsed reactor TRIGA Mainz
The performance of the upgraded solid deuterium ultracold neutron source at the pulsed reactor TRIGA Mainz is described. The current configuration stage comprises the installation of a He liquefier to run UCN experiments over long-term periods, the use of stainless steel neutron guides with improved transmission as wel...
1706.07795v2
2017-10-02
Multiple-scale structures: from Faraday waves to soft-matter quasicrystals
For many years, quasicrystals were observed only as solid-state metallic alloys, yet current research is now actively exploring their formation in a variety of soft materials, including systems of macromolecules, nanoparticles and colloids. Much effort is being invested in understanding the thermodynamic properties of ...
1710.00832v2
2017-10-12
Higher-order Fermi-liquid corrections for an Anderson impurity away from half-filling III: non-equilibrium transport
We extend the microscopic Fermi-liquid theory for the Anderson impurity [Phys.\ Rev.\ B {\bf 64}, 153305 (2001)] to explore non-equilibrium transport at finite magnetic fields. Using the Ward identities in the Keldysh formalism with the analytic and anti-symmetric properties of the vertex function, the spin-dependent F...
1710.04575v6
2017-10-13
Comparison the optical properties for Bi2O3 and NiO ultrathin films deposited on different substrates by DC sputtering technique for transparent electronics
Bismuth and Nickel transparent oxides thin films were grown on glass and flexible polythelene terephalate (PET) substrates by DC sputtering technique at room temperature 300 K. The structures of Bi2O3 and NiO films were analyzed by X-ray diffraction (XRD) analyses and scanning electron microscopy (SEM). A profilometry ...
1710.04815v1
2018-04-02
Thermal evolution and sintering of chondritic planetesimals IV. Temperature dependence of heat conductivity of asteroids and meteorites
Understanding the compaction and differentiation of the planetesimals and protoplanets from the Asteroid Belt and the terrestrial planet region of the Solar System requires a reliable modeling of their internal thermal evolution. An important ingredient for this is a detailed knowledge of the heat conductivity of the c...
1804.00574v1
2018-04-05
Phase-field modeling of equilibrium precipitate shapes under the influence of coherency stresses
Coherency misfit stresses and their related anisotropies are known to influence the equilibrium shapes of precipitates. Additionally, mechanical properties of the alloys are also dependent on the shapes of the precipitates. Therefore, in order to investigate the mechanical response of a material which undergoes precipi...
1804.01763v1
2018-04-06
Automatic Selection of Atomic Fingerprints and Reference Configurations for Machine-Learning Potentials
Machine learning of atomic-scale properties is revolutionizing molecular modelling, making it possible to evaluate inter-atomic potentials with first-principles accuracy, at a fraction of the costs. The accuracy, speed and reliability of machine-learning potentials, however, depends strongly on the way atomic configura...
1804.02150v1
2018-04-07
Analysis of Misorientation Relationships between Austenite Parents and Twins
The forward transformation from face centered cubic austenite to body centered cubic/tetragonal martensite in ferrous alloys can significantly in- fluence the microstructure and mechanical properties of the material. Inferring possible high temperature crystal orientations from observations of ambient temperature trans...
1804.02506v1
2018-04-09
Pressure effects on the structural and superconducting transitions in La3Co4Sn13
La3Co4Sn13 is a superconducting material with transition temperature at Tc = 2.70 K, which presents a superlattice structural transition at T* ~ 150 K, a common feature for this class of compounds. However, for this material, it is not clear that at T* the lattice distortions arise from a charge density wave (CDW) or f...
1804.03215v2
2018-04-12
Pt$_3$Zr(0001): A substrate for growing well-ordered ultrathin zirconia films by oxidation
We have studied the surface of pure and oxidized Pt$_3$Zr(0001) by scanning tunneling microscopy (STM), Auger electron microscopy, and density functional theory (DFT). The well-annealed alloy surface shows perfect long-range chemical order. Occasional domain boundaries are probably caused by nonstoichiometry. Pt$_3$Zr ...
1804.04405v1
2018-03-20
Nanoscience Perspective on Disorder Modifications of Superconducting Critical Temperature
Superconductivity can be modified by various effects related to randomness, disorder, structural defects, and other similar physical effects. Their affects on superconductivity are important because such effects are intrinsic to certain material system's preparation, or may be intentionally produced. In this work we sh...
1804.06226v1
2018-04-14
Investigating the Composite/Metal Interface and its Influence on the Electrical Resistance Measurement
The advantages introduced by carbon fiber reinforced polymer (CFRP) composites has made them an appropriate choice in many applications and an ideal replacement for conventional materials. The benefits using CFRP composites are due to their lightweight, high stiffness, as well as corrosion resistance. For this reason, ...
1804.06246v1